fn resolve_micro_hints(s: &Settings) -> Vec<String>Expand description
Pure resolver for the micro-break hint pool, honouring
micro_hint_mix. Physical / Psychological return only that pool;
anything else (including Both) concatenates both in
physical-then-psychological order. This does the allocating /
concatenating work; DerivedCaches caches its result so the fire
path doesn’t repeat it.